Expandable diaphragm as a cushion in loose packed bottles



April 7, 1959 B. FoYE 2,880,900

` EXPANDABLE DAPPIIRAGIVIv AS A CUSHION IN LOOSE PACKED BOTTLES Filed0G12. 3, 1955 United States Patent EXPANDABLE DIAPHRAGM AS A CUSHIONLOOSE PACKED BOTTLES Allen Bradford Foye, West Bridgewater, Mass.,assigner to W. R. Grace & Co., Cambridge, Mass., a corporation ofConnecticut Application October 3, 1955, Serial No. 538,083

1 Claim. (Cl. 215-40) This invention relates to container closures andparticularly to a closure designed to be used on jars or cans in whichsolids are packed. Presently, hard candies are packed in jars and, whena weighed amount of the candy is inserted in the jar, a crumpled pieceof waxed paper is inserted through the mouth of the jar to hold thecandies and prevent them from abrading during shipment.

Pharmaceutical products, particularly tablets, are also packed in thismanner, but usually a wad of sterile cotton instead of paper is pushedthrough the neck of the bottle just prior to the capping operation.Small mechanical parts such as watch and small radio components are alsopacked in the same manner.

The closure which I have developed eliminates the need of paper orcotton stuffing and, in addition, gives the advantage of vacuum packingto the contents. Vacuum packing prevents the absorption of moisture. Inthe case of hard candies, this is a particular advantage because thehygroscopic nature of candies causes them to stick together duringtransit. In the case of mechanical parts, it prevents the rusting ofsteel or the oxidation of other metals.

If a container is sealed under vacuum (for example in a mechanicalvacuum closing machine) and if the entire interior surface of theclosure is made of an extensible, air impervious diaphragm, thediaphragm will form the normal sealing gasket and maintain the internalvacuum; then, additionally, if a minute puncture is made through themetal only of the top panel, air pressure above the diaphragm will causeit to balloon from its restrained margins, and expand to ll theunoccupied vacuum space. It comes to rest against the irregular packingpattern of the contents. The package may be bumped and jolted, butwedged down by the balloon, the separate parts cannot move.

Should one so choose, although the cost of the pulp V` liner must beconsidered, the diaphragm may be applied over the conventional pulpliner used in many jar and cap closures. Such liners are not imperviousto air and, after the jar or the can has been closed as described, itwill be found that in a few minutes suicient aii has leaked between thethreads and through the pulp to expand the diaphragm in the same manneras when a minute hole is made through the metal.

The invention will be clear from the accompanying drawings, in which-Figure l is a vertical section through a common screw or CT jar cap,

Figure 2 is a vertical section through CT cap provided with a pulpliner,

Figure 3 is an elevation showing the improved closure applied to a jarof hard candies, and

Figure 4 is an elevation showing the invention applied to a brokenthread screw top can.

In Figure 1 the CT screw cap 10, is provided with a diaphragm 11 ofrubber or rubbery material which covers the entire inner surface of thecap. The diaphragm 11 can be made slightly thicker around the channe ornorrice mal sealing area 13, but it must extend entirely across thepanel 14.

Referring to Figure 3, the cap of Figure 1 is shown applied to a jar 15of hard candies. After the cap 10 has been applied in a vacuum closingmachine, the minute hole 16 is pierced through the panel 14, diaphragm11 expands as is shown, pressing down on the top layer of sour balls,which are now cushioned against movement.

In Figure 2 a CT cap 10a is shown provided with a pulp liner 17 overwhich the diaphragm 11a is placed. As was explained, it is not necessaryto pierce the top panel when such a closure is vacuum sealed on a jar.In a short time after sealing, enough air will have leaked through thepulp liner 17 to cause the diaphragm 11a to assume the position ofdiaphragm 11 in Figure 3.

In Figure 4, the diaphragmllb has been applied across the inner surfaceof the closure 18 of a broken-thread, removable top can 19. The minutehole 21 has allowed the diaphragm 11b to expand into and till the normalhead space in can 19.

Any material which is essentially air-impervious, extensible andsomewhat resilient so that a proper seal is formed around the mouth ofthe container is suitable as a diaphragm. There are many elastomericsubstances besides natural rubber and several plasticized resins whichmeet these requirements among which may be mentioned natural rubber,butadiene-styrene copolymers, butadiene acrylonitrile, copolymers, vinylpolymers, polyvinyl butyrals, and super polyesters of the nylon type.These may be formed or molded and inserted in the closure or they may bepoured in in liquid form and converted to a solid diaphragm by drying.

I prefer, however, to make the diaphragm from a vinyl plastisol becausethe manufacture of diaphragm lined caps can then become both rapid andsimple. The plastisol is owed into the cap by any of the conventionallining machines now used in the container closure industry, and theliquid plastisol can be liuxed" or converted to a solid diaphragm in buta few seconds by heating the closure in a properly designed oven.

Any closure which loses its liner in handling prior to capping is anindustrial nuisance. The diaphragm must be adhered to the cap suicientlyto prevent its falling out in handling prior to closing the jar. If thediaphragm is molded or cut from a sheet, it is cemented to the closureby a layer of cement applied to the channel 13 only. No cement isnecessary when latex or plastisols are used, but the degree of adhesionto the panel must be kept low. This can be achieved by various means.For example, vinyl plastisols will stick tenaciously to a vinyl base tinplate enamel, but if the enamel be oleoresinous, the mild adhesion issuicient to prevent the diaphragm from falling out during handling, butis insuficient to prevent the diaphragm from being blown away from thepanel after the panel is punctured.

Because air is admitted over the diaphragm, my closure is not operativewith top seal and other types of closures which depend upon thecontinuance of vacuum beneath the cap to hold the closure in place, butit is suitable for any closure which is provided with threads or lugs orany holding device which mechanically secures the closure to thecontainer.

Iclaim: In a sealed container including a container element and a rigidclosure element said closure element including a top closure panel and aclosure retaining skirt, means to prevent the movement of solidcontents, comprising van essentially air-impervious, extensibleelastomeric diaof said elements thereby forming a sealinggasket for saidcontainer, the rem'ai'ndelof said diaphragm being exposed to atmosphericpressure on its closureside and to subatmospheric pressure on itsvcontainer side, the said difference in pressure causing s aid remainingportion of the -diaphragm to balloon into the free space within thecontainer thereby forming a cushion packing for its contents.

References Cited in the le of this patent UNITED STATES PATENTS Griswoldetal Mar. 23, 1880 Eisen Feb. 25, 1941 Wright Apr. 7, 1942 FOREIGNPATENTS France Mar. 15,. 1950

